CD12.11 Rother and Romney CFMP.pdf - Shepway District Council
CD12.11 Rother and Romney CFMP.pdf - Shepway District Council
CD12.11 Rother and Romney CFMP.pdf - Shepway District Council
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<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment<br />
Flood Management Plan<br />
Summary Report December 2009<br />
managing<br />
flood risk
We are the Environment Agency. It’s our job to look after<br />
your environment <strong>and</strong> make it a better place – for you,<br />
<strong>and</strong> for future generations.<br />
Your environment is the air you breathe, the water you<br />
drink <strong>and</strong> the ground you walk on. Working with business,<br />
Government <strong>and</strong> society as a whole, we are making your<br />
environment cleaner <strong>and</strong> healthier.<br />
The Environment Agency. Out there, making your<br />
environment a better place.<br />
Published by:<br />
Environment Agency<br />
Guildbourne House<br />
Chatsworth Road<br />
Worthing, West Sussex BN11 1LD<br />
Tel: 08708 506 506<br />
Email: enquiries@environment-agency.gov.uk<br />
www.environment-agency.gov.uk<br />
© Environment Agency<br />
All rights reserved. This document may be reproduced<br />
with prior permission of the Environment Agency.
Introduction<br />
I am pleased to introduce our summary of the<br />
<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management<br />
Plan (<strong>CFMP</strong>). This <strong>CFMP</strong> gives an overview of the<br />
flood risk in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment <strong>and</strong><br />
sets out our preferred plan for sustainable flood<br />
risk management over the next 50 to 100 years.<br />
The <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> is one of 77 <strong>CFMP</strong>s for<br />
Engl<strong>and</strong> <strong>and</strong> Wales. Through the <strong>CFMP</strong>s, we have<br />
assessed inl<strong>and</strong> flood risk across all of Engl<strong>and</strong> <strong>and</strong><br />
Wales for the first time. The <strong>CFMP</strong> considers all types of<br />
inl<strong>and</strong> flooding, from rivers, groundwater, surface<br />
water <strong>and</strong> tidal flooding, but not flooding directly from<br />
the sea (coastal flooding), which is covered by<br />
Shoreline Management Plans (SMPs). Our coverage of<br />
surface <strong>and</strong> groundwater is however limited due to a<br />
lack of available information.<br />
The role of <strong>CFMP</strong>s is to establish flood risk<br />
management policies which will deliver sustainable<br />
flood risk management for the long term. This is<br />
essential if we are to make the right investment<br />
decisions for the future <strong>and</strong> to help prepare ourselves<br />
effectively for the impact of climate change. We will<br />
use <strong>CFMP</strong>s to help us target our limited resources<br />
where the risks are greatest.<br />
This <strong>CFMP</strong> identifies flood risk management policies to<br />
assist all key decision makers in the catchment. It was<br />
produced through a wide consultation <strong>and</strong> appraisal<br />
process, however it is only the first step towards an<br />
integrated approach to flood risk management. As we<br />
all work together to achieve our objectives, we must<br />
monitor <strong>and</strong> listen to each others progress, discuss<br />
what has been achieved <strong>and</strong> consider where we may<br />
need to review parts of the <strong>CFMP</strong>.<br />
The main source of flood risk in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong><br />
<strong>CFMP</strong> area is from both river <strong>and</strong> tidal flooding <strong>and</strong> to a<br />
lesser extent surface <strong>and</strong> ground water flooding. The<br />
main areas at risk from tidal flooding are Rye, Hythe,<br />
Folkestone, Hamstreet, Robertsbridge <strong>and</strong> Etchingham.<br />
We cannot reduce flood risk on our own, we will<br />
therefore work closely with all our partners to improve<br />
the co-ordination of flood risk activities <strong>and</strong> agree the<br />
most effective way to management flood risk in the<br />
future. The key partners we have worked with are Kent<br />
County <strong>Council</strong>, East Sussex County <strong>Council</strong>, <strong>Rother</strong><br />
<strong>District</strong> <strong>Council</strong>, <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong>, Ashford<br />
Borough <strong>Council</strong>, <strong>Romney</strong> Marsh Internal Drainage<br />
Board, Natural Engl<strong>and</strong>, English Heritage, Southern<br />
Water, National Farmers Union.<br />
This is a summary of the main <strong>CFMP</strong> document, if you<br />
need to see the full document an electronic version<br />
can be obtained by emailing<br />
enquiries@environment-agency.gov.uk or alternatively<br />
paper copies can be viewed at any of our offices in<br />
Southern Region.<br />
Toby Willison<br />
Regional Director, Southern Region<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 3
Contents<br />
The purpose of a <strong>CFMP</strong> in managing flood risk 5<br />
Catchment overview 6<br />
Current <strong>and</strong> future flood risk 8<br />
Future direction for flood risk management 11<br />
Sub-areas<br />
1 Robertsbridge <strong>and</strong> Etchingham 13<br />
2 Hamstreet 15<br />
3 <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong> Marshes 16<br />
4 Hythe <strong>and</strong> Folkestone 18<br />
5 Rye 20<br />
6 Rural <strong>Rother</strong> 21<br />
Map of <strong>CFMP</strong> policies 23<br />
4 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
The purpose of a <strong>CFMP</strong><br />
in managing flood risk<br />
<strong>CFMP</strong>s help us to underst<strong>and</strong> the<br />
scale <strong>and</strong> extent of flooding now<br />
<strong>and</strong> in the future, <strong>and</strong> set policies<br />
for managing flood risk within the<br />
catchment. <strong>CFMP</strong>s should be used<br />
to inform planning <strong>and</strong> decision<br />
making by key stakeholders such as:<br />
• The Environment Agency, who will<br />
use the plan to guide decisions<br />
on investment in further plans,<br />
projects or actions;<br />
• Regional planning bodies <strong>and</strong><br />
local authorities who can use the<br />
plan to inform spatial planning<br />
activities <strong>and</strong> emergency planning;<br />
• IDBs, water companies <strong>and</strong><br />
other utilities to help plan their<br />
activities in the wider context<br />
of the catchment;<br />
• Transportation planners;<br />
• L<strong>and</strong> owners, farmers <strong>and</strong><br />
l<strong>and</strong> managers that manage<br />
<strong>and</strong> operate l<strong>and</strong> for<br />
agriculture, conservation<br />
<strong>and</strong> amenity purposes;<br />
• The public <strong>and</strong> businesses to<br />
enhance their underst<strong>and</strong>ing<br />
of flood risk <strong>and</strong> how it will<br />
be managed.<br />
<strong>CFMP</strong>s aim to promote more<br />
sustainable approaches to managing<br />
flood risk. The policies identified in<br />
the <strong>CFMP</strong> will be delivered through a<br />
combination of different approaches.<br />
Together with our partners, we<br />
will implement these approaches<br />
through a range of delivery plans,<br />
projects <strong>and</strong> actions.<br />
The relationship between the <strong>CFMP</strong>,<br />
delivery plans, strategies, projects<br />
<strong>and</strong> actions is shown in figure 1.<br />
Figure 1. The relationship between <strong>CFMP</strong>s, delivery plans, projects <strong>and</strong> actions.<br />
Policy planning<br />
• <strong>CFMP</strong>s <strong>and</strong> Shoreline Management Plans.<br />
• Action plans define requirement for delivery<br />
plans, projects <strong>and</strong> actions.<br />
Policy delivery plans (see note)<br />
• Influence spatial planning to reduce risk<br />
<strong>and</strong> restore floodplains.<br />
• Prepare for <strong>and</strong> manage floods<br />
(including local flood warning plans).<br />
• Managing assets.<br />
• Water level management plans.<br />
• L<strong>and</strong> management <strong>and</strong> habitat creation.<br />
• Surface water management plans.<br />
Projects <strong>and</strong> actions<br />
• Make sure our spending delivers the best<br />
possible outcomes.<br />
• Focus on risk based targets, for example<br />
numbers of households at risk.<br />
Note: Some plans may not be led by us – we may<br />
identify the need <strong>and</strong> encourage their development.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 5
Catchment overview<br />
The <strong>CFMP</strong> area is situated in the<br />
South East of Engl<strong>and</strong>, covers<br />
approximately 970km2 with a<br />
population of 175,000 people.<br />
There are a number of towns within<br />
the <strong>CFMP</strong> area including Rye,<br />
Tenterden, Hythe, Dymchurch, Lydd,<br />
Robertsbridge <strong>and</strong> New <strong>Romney</strong><br />
with the major towns of Hastings<br />
<strong>and</strong> Folkestone at the edge of the<br />
<strong>CFMP</strong> area.<br />
The primary river system within the<br />
<strong>CFMP</strong> area is the River <strong>Rother</strong> along<br />
with its tributaries. The River <strong>Rother</strong><br />
rises near Mayfield in East Sussex<br />
<strong>and</strong> flows eastward extending<br />
through the towns of Robertsbridge<br />
<strong>and</strong> Etchingham. These towns have<br />
experienced severe flooding since<br />
the 1940s. The upper part of the<br />
catchment is mainly woodl<strong>and</strong> <strong>and</strong><br />
grassl<strong>and</strong>, but in some locations<br />
natural floodplains have been<br />
modified by farming <strong>and</strong> urban<br />
development with the result of<br />
increasing run-off to the lower part<br />
of the catchment. The lower <strong>and</strong><br />
eastern part of the catchment<br />
consists of a wide expanse of<br />
reclaimed coastal marshl<strong>and</strong> which<br />
lies mostly below the spring tide<br />
level.<br />
The geology of the area consist of<br />
alluvium <strong>and</strong> marine silts in the<br />
<strong>Rother</strong> <strong>and</strong> Wall<strong>and</strong> Marshes with<br />
Gault clay <strong>and</strong> Chalk in eastern<br />
extremity of <strong>Romney</strong> Marsh.<br />
Hastings Beds in the High Weald<br />
<strong>and</strong> shingle headl<strong>and</strong> of Dungeness<br />
extending into the English Channel.<br />
There are six sub-areas each with a<br />
preferred policy that divide the<br />
catchment area; the Robertsbridge<br />
<strong>and</strong> Etchingham, Hamstreet, Rye,<br />
<strong>Rother</strong> <strong>and</strong> Wall<strong>and</strong> Marshes, Hythe<br />
<strong>and</strong> Folkestone <strong>and</strong> Rural <strong>Rother</strong>.<br />
View south of rural <strong>Rother</strong> near<br />
Udimore, Kent.<br />
➜<br />
6 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
Map 1. Overview map of <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment.<br />
‘The north <strong>and</strong> west of the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong><br />
catchment is part of the High Weald, mainly woodl<strong>and</strong>,<br />
grassl<strong>and</strong> <strong>and</strong> natural floodplains, while the south <strong>and</strong><br />
east are characterised by a wide expanse of reclaimed<br />
coastal marshl<strong>and</strong>.’<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 7
➜<br />
Current <strong>and</strong> future flood risk<br />
Overview of the current<br />
flood risk<br />
Flood risk is the combination of the<br />
probability of flooding <strong>and</strong> its<br />
impact, that is, the chance of it<br />
happening <strong>and</strong> the consequences if<br />
it does happen. We have assessed<br />
flood risk across the <strong>CFMP</strong> area<br />
using broad-scale computer<br />
modelling, though making best use<br />
of existing knowledge <strong>and</strong> models<br />
where appropriate. Flood risk<br />
figures take into account current<br />
flood defences.<br />
The flood generation mechanism<br />
within the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong><br />
area varies in relation to both the<br />
watercourse <strong>and</strong> the location within<br />
the catchment. Significant flooding<br />
problems are associated with the<br />
urban areas of Robertsbridge,<br />
Etchingham <strong>and</strong> Hamstreet.<br />
Robertsbridge has suffered ever<br />
increasing flooding since 1946.<br />
Where is the risk?<br />
This map in page 10 illustrates the<br />
consequences of a 1% annual<br />
probability flood event (1 in 100<br />
year) occurring in the <strong>CFMP</strong> area.<br />
The areas with the highest<br />
concentration of properties at risk<br />
from river flooding are tabulated<br />
on page 9.<br />
Figure 2. Current <strong>and</strong> future (2100) flood risk to property from a 1% annual<br />
probability river flood, taking into account current flood defences.<br />
Number of properties at flood risk<br />
3000<br />
2500<br />
2000<br />
1500<br />
1000<br />
500<br />
0<br />
Current<br />
Robertsbridge <strong>and</strong><br />
Etchingham<br />
Future<br />
Hamstreet<br />
Hythe <strong>and</strong><br />
Folkestone<br />
Rye<br />
In the lower <strong>Rother</strong> catchment there<br />
are several minor tributaries <strong>and</strong><br />
drains that can cause isolated flood<br />
incidents <strong>and</strong> the <strong>Romney</strong> <strong>and</strong><br />
Wall<strong>and</strong> Marshes are prone to both<br />
river <strong>and</strong> coastal flooding.<br />
High waters on the River <strong>Rother</strong>.<br />
8 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
How we currently<br />
manage the risk<br />
The area is very low lying <strong>and</strong> there<br />
is a network of channels, drains,<br />
<strong>and</strong> structures which together with<br />
the Royal Military Canal combine to<br />
drain the area for agricultural use.<br />
There are also a number of small<br />
steep urban catchments <strong>and</strong><br />
existing defence infrastructure<br />
acts to defend the urban areas<br />
at risk. We are therefore looking<br />
for opportunities to revert the<br />
catchment back to its natural state.<br />
Our activity is prioritised on a risk<br />
basis <strong>and</strong> our main activities<br />
include:<br />
Table 1. Locations of towns <strong>and</strong> villages with 25 or more properties at risk<br />
in a 1% annual probability river flood.<br />
Number of properties at risk<br />
Table 2. Critical infrastructure at risk:<br />
Locations<br />
>1000 Rye, Hythe <strong>and</strong> Folkestone<br />
500 to 1000 None<br />
100 to 500 None<br />
50 to 100 Robertsbridge <strong>and</strong> Etchingham,<br />
Hamstreet<br />
25 to 50 None<br />
• Maintenance of existing <strong>and</strong><br />
commission of new flood<br />
defences <strong>and</strong> structures such as<br />
the flood alleviation scheme<br />
constructed 2003 in<br />
Robertsbridge. The scheme<br />
composed of approximately<br />
1,160 m of earth embankment,<br />
680 m of floodwalls <strong>and</strong> 430m<br />
of river realignment to protect<br />
the northern, central <strong>and</strong><br />
southern parts of the town from<br />
river flooding.<br />
• Flood forecasting <strong>and</strong> warnings,<br />
much of the data collected from<br />
the gauges that we operate,<br />
inform the flood warnings issued<br />
through the Flood Warnings<br />
Direct system to emergency<br />
services, parish councils,<br />
business <strong>and</strong> householders in<br />
key areas.<br />
1 emergency service, 6 schools<br />
Table 3. Designated sites at risk:<br />
Dungeness SAC<br />
• Development control, significant<br />
developments are not planned in<br />
the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong><br />
area. Any further developments<br />
must be supported by a flood<br />
risk assessment that also shows<br />
that the development will not<br />
increase flood risk elsewhere.<br />
• Flood risk mapping, has<br />
historically concentrated on the<br />
Rivers <strong>Rother</strong>, Darwell <strong>and</strong><br />
Dudwell. We are planning to<br />
develop a more accurate digital<br />
terrain model of the Marshes<br />
area to be used to estimate the<br />
extent, depth <strong>and</strong> duration of<br />
flooding, flood hazard <strong>and</strong> the<br />
river <strong>and</strong> coastal interactions.<br />
• Strategic planning to plan long<br />
term investment<br />
• Environmental improvements.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 9
Map 2. Flood risk to property in a 1% annual probability river flood, taking into account current flood defences.<br />
The impact of climate change <strong>and</strong> future flood risk<br />
The effect that flooding will have in<br />
the future is influenced by a range<br />
of issues such as climate change,<br />
changes in l<strong>and</strong> use such as<br />
development, <strong>and</strong> changes in how<br />
l<strong>and</strong> is managed.<br />
Predictions of future change are<br />
based on underst<strong>and</strong>ing the<br />
existing condition of the catchment,<br />
an extrapolation of trends over the<br />
long term (up to 100 years), <strong>and</strong> a<br />
high level review of likely future<br />
change based on research findings<br />
<strong>and</strong> knowledge. There are only a few<br />
sites identified for development<br />
within the catchment area, therefore<br />
the modelled impact of urbanisation<br />
on future flood risk in the <strong>Rother</strong> <strong>and</strong><br />
<strong>Romney</strong> <strong>CFMP</strong> area is negligible.<br />
L<strong>and</strong> use <strong>and</strong> l<strong>and</strong> use management<br />
changes such as afforestation could<br />
reduce peak flow <strong>and</strong> flood volume<br />
the upper <strong>Rother</strong> catchment,<br />
conversely, the likely effect of an<br />
agricultural intensification is to<br />
increase peak flow <strong>and</strong> flood volume<br />
upper parts of the catchment. From<br />
the three drivers tested, climate<br />
change has the largest impact on the<br />
<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> catchment<br />
with up to 20% increase in peak flood<br />
flows. This scenario is used to assess<br />
likely impacts in the catchment. In<br />
the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment<br />
the future flood risk is likely to be<br />
from river flooding <strong>and</strong> surface water<br />
flooding. Our appraisal of the future<br />
risk in the catchment reveals the<br />
number of properties at risk to the<br />
1% annual probability event will<br />
increase from 151 to 179 properties<br />
by the year 2100. The majority of<br />
these properties are located in<br />
Robertsbridge, Etchingham <strong>and</strong><br />
Hamstreet. Please note the broadscale<br />
modelling indicates there are large<br />
numbers of properties at risk in Rye,<br />
Hythe <strong>and</strong> Folkestone, however<br />
these figures do not differentiate<br />
between coastal <strong>and</strong> river flooding.<br />
The key trends are:<br />
• More frequent <strong>and</strong> intense<br />
storms causing more widespread<br />
<strong>and</strong> regular flooding from drainage<br />
systems <strong>and</strong> some rivers.<br />
• More rain in winter, increasing<br />
the likelihood of large scale<br />
flood events.<br />
10 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
Future direction for<br />
flood risk management<br />
Approaches in each sub-area<br />
We have divided the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment into six distinct<br />
sub-areas which have similar physical characteristics, sources of flooding<br />
<strong>and</strong> level of risk. We have identified the most appropriate approach to<br />
managing flood risk for each of the sub-areas <strong>and</strong> allocated one of six<br />
generic flood risk management policies, shown in Table 4.<br />
To select the most appropriate policy, the plan has considered how social,<br />
economic <strong>and</strong> environmental objectives are affected by flood risk<br />
management activities under each policy option.<br />
Map 3. Sub-areas <strong>and</strong> flood risk management policies.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 11
Table 4. Policy options.<br />
➜ Policy 1<br />
Areas of little or no flood risk where we will continue to monitor <strong>and</strong> advise<br />
This policy will tend to be applied in those areas where there are very few properties at risk of flooding. It reflects a<br />
commitment to work with the natural flood processes as far as possible.<br />
➜ Policy 2<br />
Areas of low to moderate flood risk where we can generally reduce existing flood risk management actions<br />
This policy will tend to be applied where the overall level of risk to people <strong>and</strong> property is low to moderate. It may<br />
no longer be value for money to focus on continuing current levels of maintenance of existing defences if we can<br />
use resources to reduce risk where there are more people at higher risk. We would therefore review the flood risk<br />
management actions being taken so that they are proportionate to the level of risk.<br />
➜ Policy 3<br />
Areas of low to moderate flood risk where we are generally managing existing flood risk effectively<br />
This policy will tend to be applied where the risks are currently appropriately managed <strong>and</strong> where the risk of<br />
flooding is not expected to increase significantly in the future. However, we keep our approach under review,<br />
looking for improvements <strong>and</strong> responding to new challenges or information as they emerge. We may review our<br />
approach to managing flood defences <strong>and</strong> other flood risk management actions, to ensure that we are managing<br />
efficiently <strong>and</strong> taking the best approach to managing flood risk in the longer term.<br />
➜ Policy 4<br />
Areas of low, moderate or high flood risk where we are already managing the flood risk effectively but where we<br />
may need to take further actions to keep pace with climate change<br />
This policy will tend to be applied where the risks are currently deemed to be appropriately-managed, but where<br />
the risk of flooding is expected to significantly rise in the future. In this case we would need to do more in the<br />
future to contain what would otherwise be increasing risk. Taking further action to reduce risk will require further<br />
appraisal to assess whether there are socially <strong>and</strong> environmentally sustainable, technically viable <strong>and</strong><br />
economically justified options.<br />
➜ Policy 5<br />
Areas of moderate to high flood risk where we can generally take further action to reduce flood risk<br />
This policy will tend to be applied to those areas where the case for further action to reduce flood risk is most<br />
compelling, for example where there are many people at high risk, or where changes in the environment have<br />
already increased risk. Taking further action to reduce risk will require additional appraisal to assess whether there<br />
are socially <strong>and</strong> environmentally sustainable, technically viable <strong>and</strong> economically justified options.<br />
➜ Policy 6<br />
Areas of low to moderate flood risk where we will take action with others to store water or manage run-off in<br />
locations that provide overall flood risk reduction or environmental benefits<br />
This policy will tend to be applied where there may be opportunities in some locations to reduce flood risk locally<br />
or more widely in a catchment by storing water or managing run-off. The policy has been applied to an area (where<br />
the potential to apply the policy exists), but would only be implemented in specific locations within the area, after<br />
more detailed appraisal <strong>and</strong> consultation.<br />
12 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
Sub-area 1<br />
Robertsbridge <strong>and</strong> Etchingham<br />
Our key partners are:<br />
<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk 65 83<br />
The issues in this<br />
sub-area<br />
The Etchingham <strong>and</strong> Robertsbridge<br />
sub-area covers these villages<br />
situated on the <strong>Rother</strong>. The sub-area<br />
extends approximately one<br />
kilometre upstream of the<br />
confluence of the Rivers <strong>Rother</strong> <strong>and</strong><br />
Darwell, to approximately one<br />
kilometre downstream of the A21<br />
crossing in Robertsbridge.<br />
The impact on flooding of new<br />
development depends on the<br />
implementation of Sustainable urban<br />
Drainage Systems (SuDS), which is of<br />
particular importance as surface<br />
water flooding due to overloaded<br />
drainage is already a problem.<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 3 – areas of low to<br />
moderate flood risk where we are<br />
generally managing existing flood<br />
risk effectively.<br />
➜<br />
Robertsbridge<br />
flood alleviation<br />
scheme.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 13
The key messages<br />
The chosen policy will aim to maintain the numbers of properties <strong>and</strong> people considered to be at flood risk <strong>and</strong> the<br />
duration <strong>and</strong> severity of impacts upon transport, infrastructure, public assets <strong>and</strong> amenities.<br />
It is important that there is no increase in surface water run-off from new development <strong>and</strong> existing development.<br />
Therefore we must seek opportunities to reduce run-off.<br />
Proposed actions to implement the preferred approach:<br />
• Provide Development Control advice to ensure no increase in run-off from new developments <strong>and</strong> seek<br />
opportunities to reduce current run-off rates where appropriate. Limited development in the floodplain is<br />
planned in this policy unit.<br />
• Develop a System Asset Management Plan (SAMP). This plan should aim to maintain flood risk at the<br />
current level.<br />
Robertsbridge<br />
flood alleviation<br />
scheme.<br />
➜<br />
14 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
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Sub-area 2<br />
Hamstreet<br />
Our key partners are:<br />
Ashford Borough <strong>Council</strong><br />
Southern Water<br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk 79 96<br />
The issues in this<br />
sub-area<br />
The Hamstreet policy unit covers<br />
this small urban area to the<br />
confluence of the Speringbrook<br />
Sewer with the Royal Military Canal.<br />
Flooding in Hamstreet is caused by<br />
a combination of river, surface <strong>and</strong><br />
groundwater sources. The<br />
Speringbrook Sewer <strong>and</strong> other<br />
surface water channels flow through<br />
the town draining a small clay<br />
catchment. Due to the nature of the<br />
clay soil <strong>and</strong> low lying l<strong>and</strong>,<br />
groundwater levels are close to the<br />
surface <strong>and</strong> storms can produce<br />
flooding very quickly, generating<br />
high water levels in the<br />
Speringbrook Sewer. Insufficient<br />
capacity of the local drainage<br />
system then causes flooding in<br />
several areas of Hamstreet.<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 3 – areas of low to<br />
moderate flood risk where we are<br />
generally managing existing flood<br />
risk effectively.<br />
The key messages<br />
The chosen policy will aim to<br />
maintain the numbers of properties<br />
<strong>and</strong> people considered to be at<br />
flood risk <strong>and</strong> the duration <strong>and</strong><br />
severity of impacts upon transport,<br />
infrastructure, public assets <strong>and</strong><br />
amenities.<br />
It is important that there is no<br />
increase in surface water run-off<br />
from new development <strong>and</strong> existing<br />
development seek to reduce run-off.<br />
Maintenance of assets ought to<br />
ensure the current st<strong>and</strong>ard of<br />
protection is upheld to<br />
accommodate flooding due to<br />
climate change.<br />
Duck pond at Hamstreet.<br />
Proposed actions to<br />
implement the preferred<br />
approach:<br />
• We will need to work with Ashford<br />
Borough <strong>Council</strong> <strong>and</strong> Southern<br />
Water to develop Surface Water<br />
Management Plan (SWMP) for<br />
Hamstreet. This will address<br />
surface water flows <strong>and</strong> the link<br />
between the Speringbrook Sewer<br />
<strong>and</strong> the Royal Military Canal.<br />
• Undertake System Asset<br />
Management Plans (SAMPs) to<br />
review maintenance regimes <strong>and</strong><br />
to maintain current level of<br />
investment.<br />
• Provide development control<br />
advice to ensure no increase in<br />
run-off from new developments<br />
<strong>and</strong> seek opportunities to reduce<br />
current run-off rates where<br />
appropriate. There has been<br />
recent <strong>and</strong> extensive<br />
development in this unit.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 15
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Sub-area 3<br />
<strong>Romney</strong> <strong>and</strong><br />
Wall<strong>and</strong> Marshes<br />
Our key partners are:<br />
<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />
Ashford Borough <strong>Council</strong> <strong>and</strong><br />
<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />
Natural Engl<strong>and</strong><br />
Internal Drainage Board<br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk Minimal Minimal<br />
The issues in this<br />
sub-area<br />
This policy unit covers the low lying<br />
areas of <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong><br />
Marshes, including <strong>and</strong> bounded by<br />
the Royal Military Canal to the north<br />
<strong>and</strong> east, <strong>and</strong> the outfall of the<br />
<strong>Rother</strong> to the south. The Nickolls<br />
Quarry site is included within this<br />
policy unit. The area is very low lying<br />
<strong>and</strong> flat. The flood risk is complex,<br />
as the area is at risk of from both<br />
river <strong>and</strong> coastal flooding. A<br />
complex network of drains <strong>and</strong><br />
management of water levels in the<br />
Royal Military Canal control water<br />
movement within the Marshes. The<br />
current level of flood risk from river<br />
flooding is relatively low in this<br />
area, <strong>and</strong> the number of properties<br />
within this policy unit affected by<br />
river flooding is minimal.<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 3 – areas of low to<br />
moderate flood risk where we are<br />
generally managing existing flood<br />
risk effectively.<br />
View across Wall<strong>and</strong> Marsh.<br />
16 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
➜<br />
The key messages<br />
The chosen policy supports economic <strong>and</strong> social sustainability by prioritising significant gains elsewhere with the<br />
acceptance for some potential for future minor losses within the sub-area.<br />
Proposed actions to implement the preferred approach:<br />
• Undertake System Asset Management Plans (SAMPs) to review maintenance regimes <strong>and</strong> to maintain curent<br />
level of investment.<br />
• We will need to week with Natural Engl<strong>and</strong> to create wetl<strong>and</strong> habitat.<br />
• Support the development <strong>and</strong> recommendations of the Wall<strong>and</strong> Marsh, Dungeness <strong>Romney</strong> Marsh, Rye Bay<br />
<strong>and</strong> <strong>Romney</strong> Warren Water Level Management Plans (WLMPs).<br />
• Undertake depth, duration <strong>and</strong> hazard mapping on <strong>Romney</strong> Marsh, including looking at coastal <strong>and</strong> river<br />
interactions. To improve the underst<strong>and</strong>ing of flood depths <strong>and</strong> hazard on the marshes.<br />
Outfall at Dymchurch, <strong>Romney</strong> <strong>and</strong> Wall<strong>and</strong> Marshes.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 17
Sub-area 4<br />
Hythe <strong>and</strong> Folkestone<br />
Our key partners are:<br />
<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />
Southern Water<br />
The issues in this<br />
sub-area<br />
This policy unit covers the urban<br />
area of Hythe, <strong>and</strong> the area of<br />
Folkestone which is not part of the<br />
Stour <strong>CFMP</strong>. This is a small urban<br />
policy unit. Current predictions are<br />
for storm intensity to increase due<br />
to climate change, therefore flood<br />
risk is expected to increase in<br />
the future.<br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk 2085 2444*<br />
*Figures are predominantly due to coastal flooding <strong>and</strong> excludes the<br />
presence of flood defences. Derived from floodzone 3 which does not<br />
distinguish between river <strong>and</strong> coastal flooding.<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 4 – areas of low,<br />
moderate or high flood risk where<br />
we are already managing the flood<br />
risk effectively but where we may<br />
need to take further actions to keep<br />
pace with climate change.<br />
➜<br />
Royal Military Canal looking west,<br />
through Hythe.<br />
18 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
➜<br />
The key messages<br />
This policy applies where the current risk is acceptable but future changes are expected to have a significant<br />
impact. Flood risk management activities need to respond to the potential increases in flood risk.<br />
Proposed actions to implement the preferred approach:<br />
• Improve underst<strong>and</strong>ing of the watercourses that were previously ordinary watercourses within this policy unit.<br />
• We will need to work with <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong> to develop a System Asset Management Plan (SAMP).<br />
This plan should aim to maintain flood risk at the existing level taking climate change into account.<br />
• We will need to work with Southern Water <strong>and</strong> <strong>Shepway</strong> <strong>District</strong> <strong>Council</strong> to develop a Surface Water<br />
Management Plan (SWMP) for Folkestone <strong>and</strong> Hythe.<br />
• Provide development control advice to ensure no increase in run-off from new developments <strong>and</strong> seek<br />
opportunities to reduce current run-off rates where appropriate.<br />
Royal Military canal looking east, through Hythe.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 19
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Sub-area 5<br />
Rye<br />
Our key partners are:<br />
<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />
Southern Water<br />
Natural Engl<strong>and</strong><br />
The issues in this<br />
sub-area<br />
The Rye policy unit covers this urban<br />
area at the confluence of the Rivers<br />
<strong>Rother</strong>, Brede <strong>and</strong> Tillingham. Flood<br />
risk in Rye is high, with approximately<br />
1,190 properties lying within the 1 in<br />
100 year flood event floodplain (note<br />
that this does not distinguish<br />
between river <strong>and</strong> coastal flooding,<br />
<strong>and</strong> excludes the presence of flood<br />
defences). Flooding is largely<br />
caused by rivers, although tide<br />
locking effects can be significant <strong>and</strong><br />
will increase with rising sea levels.<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 4 – areas of low,<br />
moderate or high flood risk where<br />
we are already managing the flood<br />
risk effectively but where we may<br />
need to take further actions to keep<br />
pace with climate change.<br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk 1190 1428*<br />
*Future scenario figure extrapolated from similar cathment modelling in<br />
Southern region.<br />
Proposed actions to implement the preferred<br />
approach:<br />
• Provide development control advice to ensure no increase in run-off<br />
from new developments <strong>and</strong> seek opportunities to reduce current<br />
run-off rates where appropriate. Considerable l<strong>and</strong> is required for<br />
development in this policy unit.<br />
• Develop a System Asset Management Plan (SAMP). This plan should<br />
aim to maintain flood risk at the existing level taking climate change<br />
into account.<br />
• We will need to work in partnership with <strong>Rother</strong> <strong>District</strong> <strong>Council</strong> <strong>and</strong><br />
Southern Water to develop a Surface Water Management Plan (SWMP)<br />
for Rye. This will address the important issue of surface water flooding<br />
in this unit.<br />
• Support the development <strong>and</strong> recommendations of the Rye Harbour<br />
SSSI Water Level Management Plan (WLMP). Support the development<br />
of the WLMP for the new Dungeness, <strong>Romney</strong> Marsh <strong>and</strong> Rye Bay Site of<br />
Special Scientific Interest (SSSI). Water Level Management Plans are key<br />
for managing flood risk <strong>and</strong> biodiversity needs in this unit.<br />
The key messages<br />
This policy applies where the current<br />
risk is acceptable but future changes<br />
are expected to have a significant<br />
impact. Flood risk management<br />
activities need to respond to the<br />
potential increases in flood risk.<br />
Sluice Gate on the River Tillingham, Rye.<br />
20 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
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Sub-area 6<br />
Rural <strong>Rother</strong><br />
Our key partners are:<br />
Wealden <strong>District</strong> <strong>Council</strong><br />
<strong>Rother</strong> <strong>District</strong> <strong>Council</strong><br />
Ashford Borough <strong>Council</strong><br />
Tunbridge Wells Borough <strong>Council</strong><br />
<strong>Shepway</strong> <strong>District</strong> <strong>Council</strong><br />
Natural Engl<strong>and</strong><br />
Internal Drainage Board<br />
The issues in this<br />
sub-area<br />
This policy unit covers areas of the<br />
<strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> <strong>CFMP</strong> that are<br />
not covered by the other policy<br />
units. In the past there has been<br />
little or no risk of flooding from<br />
rivers, surface water or foul water<br />
flooding. Three to four properties<br />
have been known to flood from the<br />
Marsham Sewer at the base of Chick<br />
Hill, near Cliff End.<br />
Impact of a 1% annual probability flood event<br />
Today Future (2100)<br />
Number of properties at risk Minimal Minimal<br />
The vision <strong>and</strong><br />
preferred policy<br />
Policy Option 6 – areas of low to<br />
moderate flood risk where we will<br />
take action with others to store<br />
water or manage run-off in locations<br />
that provide overall flood risk<br />
reduction or environmental<br />
benefits.<br />
The key messages<br />
River flood risk is low. We will seek<br />
opportunities for more sustainable<br />
flood risk management activities in<br />
this policy unit.<br />
View North across Rural <strong>Rother</strong>, near Udimore village.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 21
➜<br />
Proposed actions to implement the preferred approach:<br />
• Support the development <strong>and</strong> recommendations of the Rye Harbour <strong>and</strong> Pett Level SSSI Water Level<br />
Management Plans (WLMP). Support the development of the WLMP for the new Dungeness, <strong>Romney</strong> Marsh <strong>and</strong><br />
Rye Bay Sites of Special Scientific Interest (SSSI). WLMPs are key for managing flood risk <strong>and</strong> biodiversity needs<br />
in this unit.<br />
• Develop a System Asset Management Plan (SAMP). This plan should aim to increase the frequency of flooding<br />
to deliver benefits elsewhere. For example, investigate areas identified in the High Weald integrated catchment<br />
management <strong>and</strong> river restoration study where wetl<strong>and</strong> habitat or washl<strong>and</strong>s can help to reduce flooding.<br />
(Link with the regional habitat creation programme, River <strong>Rother</strong> restoration strategy <strong>and</strong> <strong>Rother</strong> - the potential<br />
for the integrated management of rural floodplains project).<br />
• Investigate opportunities to work with l<strong>and</strong>owners to create wetl<strong>and</strong> habitat, The High Weald integrated<br />
catchment management <strong>and</strong> river restoration study should be updated with data review <strong>and</strong> ground truthing<br />
to prioritise sites for further investigation. (Link with the regional habitat creation programme, River <strong>Rother</strong><br />
restoration strategy <strong>and</strong> <strong>Rother</strong>- the potential for the integrated management of rural floodplains project).<br />
Flooded fields within Rural <strong>Rother</strong>, off the Udimore road.<br />
22 Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan
Map of <strong>CFMP</strong> policies<br />
Map of the policies in the <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> catchment.<br />
Environment Agency <strong>Rother</strong> <strong>and</strong> <strong>Romney</strong> Catchment Flood Management Plan 23
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